火焰原子吸收光谱法测定粗锌中铁

摘要

The crude zinc sample was dissolved with 20 mL of hydrochloric acid and 2 drops of 30％ hydrogen peroxide.The determination method of iron in crude zinc sample by air-acetylene flame atomic absorption spectrometry (FAAS) at 248.3 nm was established in 5％ (volume fraction) hydrochloric acid solution as determination medium.Under the selected instrumental conditions,the mass concentration of iron in range of 0.20-3.00 μg/mL had good linear relationship with the corresponding absorbance.The correlation coefficient was 0.999 6,and the detection limit was 0.02 μg/mL.The interference test indicated that the determination of iron was not interfered by zinc matrix and other impurity elements.The proposed method was applied to the determination of iron in crude zinc with mass fraction of 0.001％-0.50％.The relative standard deviations (RSD,n=11) of results were between 1.0％ and 3.4％.The content of iron in actual crude zinc sample was determined according to the experimental method.The found results were basically consistent with those obtained by spectrophotometry in national standard GB/T 12689.5-2004.%采用20 mL盐酸(1+2)和2滴30％过氧化氢溶解粗锌样品,以体积分数为5％的盐酸为测定介质,使用空气-乙炔火焰,选定248.3 nm为测定波长,建立了火焰原子吸收光谱法(FAAS)测定粗锌样品中铁的方法.在选定的仪器条件下,铁在0.20～3.00 μg/mL范围内与其对应的吸光度呈良好的线性关系,相关系数为0.999 6,方法检出限为0.02 μg/mL.干扰试验表明,锌基体和其他杂质元素均不干扰铁的测定.将实验方法应用于粗锌中质量分数在0.001％～0.50％之间铁的测定,结果的相对标准偏差(RSD,n=11)在1.0％～3.4％之间.采用实验方法对粗锌实际样品中铁进行测定,测得结果与国家标准GB/T 12689.5-2004中分光光度法的结果基本一致.